Spark-plug.



S. M. KITCHEN & N. J. HOAG. SPARKPLUG. y I APPLICATION FILED 1AN.5, 1914. 1.147,24?. Patented July 2o, 1915.

/N VIENTO/c5 Afm/21175K y /,7 E A w W/T/VESSES SAMUEL MI. KITCHEN AND NORMAN J'. HOAG, OF SKANEATELES, NEW YORK.

SPARK-PLUG.

Specication of Letters Patent.

Application led J'anuary 5, 1914. Serial No. 810,279.

To all whom t may cof fera.'

Be it known that we, SAMUEL M. KITCHEN and NORMAN J. HOAG, citizens, respectively,

provements in the devices shown and de? scribed in pending application, Serial Number 808,697 iiled December 26, 1913.

The object of the invention is to provide novel, simple and effective-means for preventing the accumulation of soot or carbon 0 lng points. l

at or about the sparking end of the plug.

A further object is to'provide a metal sleeve which surrounds and is insulated from the projecting end of the central conductor, for attracting the heat yof the combustion for consuming the smoke and oil which gathers around the spark plug during and after each explosion of the gases in the engine cylinder, the said sleeve preferably serving as one of the electrodes and contacting with or forming a part of the outer casing of the plug. And a further object is to provide a spark-plug which is substanf tially solid having no cavities or chambers for gathering either soot or carbon.

The various features and parts of the invention will be understood from the detailed description which follows, and by reference to the accompanying drawing,

which forms a part of the specification, and in which- A Figure l is an elevation of the complete spark-plug having our improvement ap' plied; showing.the sleeve slotted and detachable from the casing. Fig. 2 is a central longitudinal section; showing the construction and arrangement of the parts of the same. Fig. 3 is a bottom-end view of 4the plug. Fig. 4 is a sectional view; showing the slotted sleeve integral with the casing. Figs. 5, 6 and 7 are detail views; showing modified forms of the heatingsleeve. Fig. 8 is a sectional view; showing a plain slee. e int al with the casing. Fig. 9 is a section; s owing the slotted sleeve and independent electrodes carried by the casing.'

Fig. 410 is a bottom end View; showing a modified arrangement of the electrodes carried by the central conductor, coperating with the plain sleeve of Fig. 8, for producing the sparks.

Our improved spark-plug is preferably solid, as distinguished from the usual chambered or hollow plugs in common use. By making our plugs solid, we avoid the danger of leakage of the pressure from the cylinder, due to the uneven shrinking of the different materials comprising the core and the shell, when the plugs become heated up,v

and furthermore, `owing to the novel and effective means-we provide for burning up' the smoke, oil and soot resulting from the explosion `in the engine, our plugs do not need any chambers or cavities for gathering or Adrawing the carbon away from the spark- In the drawing, 2 represents the outer con- Patented .nay ao, reis.

ductor comprising the casing or shell of the plug, which is bored out centrally at 3, to receive certain parts. One end of the 'shell is threaded at 11 for securing the plug to the engine cylinder (not shown) while'the opposite end is formed angular to'receive a 4 wrench for applying and removing the plug.

5 .represents the inner or central conductor, comprising a steel or ironrod of greater length than the shell 2, which is disposed concentrically in the shell 2 and is insulated therefrom by mica or other suitable nonconducting material 6, which substantially iills the bore 3, as best seen in Fig.A 2., The rod 5 projects beyond each end of the casing 2, and its lower end is formed into. a head 7, which supports one or more terminals or electrodes 8 which project laterally. The

opposite end of rod 5 is threaded to receive nuts 9 and 10 between which a wire -11 is held, the said wire supplying the electric current for` producing the sparks. Between the head 7 and the end L1 of the casing 2 is disposed a cylindrical insulation 12, and be tween the nut 9 and the opposite end of the casing a similar insulation 13 is disposed. The tightening `up of the nut 9 draws the parts 12 and 13 tightly against the opposite ends of the casing 2, and thus holds the plug in the assembled form shown in Figs. 1 and 2 To eifectually prevent the gathering of soot or carbon -on the lower end /1 of the casing, the head 7, or the insulation 12, all vcf tween the fingers are which are exposed to the smoke and other products of the combustion, we provide -a sleeve or thimble 14, which in its preferred form consists of a metal cylinder which is slotted longitudinally, for providing a plurality of tongues or fingers 15, the latter being integral with a ring preferably being made fast to the casing by pins 17. The sleeve 14 preferably tightly fits the insulation 12, and the free ends of the fingers 15 approach to' Within a short distance of the head 7. The sparking takes place at the gaps between the free ends of the electrodes 8 and the adjacentfingers 15. In practice the 'best results are obtained when the breadth ofthe fingers 15 and the spaces beboth about one-sixteenth of an inch. The thickness of the sleeve should be less than one-sixteenth of an inch, otherwise the sleeve will not attain the proper heat during the short intervals of the explosions for burning up the smoke and oil which finds its way to the exposed end of the plug.

1n Fig. 4, the sleeve 18 is made integral with the lower end of the casing 2', and this sleeve is also slotted like in Figs. 1, 2 and 3, While in Fig. 8 the sleeve 18 is also integral 'with the casing, but this sleeve is a plain cylinder. In the latter form the sleeve must be quite thin, say less than one-twentieth of an inch so asto heat up quickly at each firing of the cylinder, as described.

In Fig. 5 we have shown a detachable sleeve 14, similar to part 14, in which the barrel of the sleeve is caged. Fig. 6 "shows a sleeve 16 that is perforated, and in Fig.

7 the sleeve 16 consists of woven wire. All

Copies of thia'patent may be obtained for of the di'erently constructed sleeves will do' the required work, but we prefer to employ the sleeves 14 having the narrow free-end fingers 15, for the reason that the tips of the fingers 15 become heated up to the eX- tent required to consume the smoke and soot more quickly and attain a higher degree of heat than when the pointsvof the fingers are joined together, or the free ends of the sleeves are made continuous, as shown in the modified views.

By provldlng the sleeves as hereln shown,

lthe space between the head 7 and the 4free end of the sleeve is substantially uniform. In this way the Whole area of the sparking end of the plug is protected against the accumulation of soot or carbon to the same extent, which is very essential to the perfect working of the improvement, and overcomes a serious objection to the wire coils used for the same purpose, as shown in the pending application referred to.

Fig. 9 illustrates a modification which consists of slightly reducing the length of the sleeve 14', and the providing of independent electrodes 19, which depend from the casing and which receive the sparks which jump from the ends of the electrodes 20 carried by the central conductor 5.

Having thus described our invention, what We claim as new and desire to secure by Letters Patent, is-

In a spark-plug, the combination of the inner and outer conductors arranged concentrically, one of said conductors projecting beyond each end of the other conductor, and having ahead supporting -a plurality of electrodes, an insulator separating said head from the adjacent end of the outer conductor, and a metallic heating element com- 'prising a thimble telescoping said insulator one end of said thimble engaging said outer conductor the opposite end of said thimble slotted longitudinally for providing a plurality of narrow fingers whose tips substantially encircle the said head, and certain of said fingers approaching close to said electrodes for forming the spark gaps.

1n testimony whereof we affix our signatures in presence of two witnesses.

SAMUEL M. KITCHEN. NORMAN J. HOAG.

' Witnesses:

HOWARD V. RULIsoN. HARRY DE "WALLACE ve cents each, by addressing the Commissioner 'of Patents,

Washington, D. C. 

